Complementary Reverse Order Filter for CWDM Signal Loss
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Solution Overview
Problem
Coarse wavelength division multiplexing (CWDM) optical systems experience significant optical signal losses due to uneven optical path lengths and the number of bounces, leading to varying power losses across different wavelengths.
Innovation Solution
The implementation of a complementary reverse order (CRO) filter, which reverses the order of filter regions on the transmission and reception sides, ensuring that all wavelengths have a comparable optical path length and number of bounces, thereby reducing maximum optical signal losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional filter order is used in CWDM systems, then device complexity is reduced, but optical signal loss increases due to uneven optical path lengths and varying number of bounces across different wavelengths
Solution Approach 1:
The patent applies inversion by reversing the order of filter regions in the reception side filter relative to the transmission side filter. Specifically, if the transmission filter has regions arranged in wavelength order (e.g., 990nm, 1020nm, 1050nm, 1080nm), the reception filter has regions arranged in reverse wavelength order (e.g., 1080nm, 1050nm, 1020nm, 990nm). This inversion equalizes the optical path lengths and number of bounces for all wavelengths, reducing maximum optical signal loss from 14 bounces to 8 bounces in a four-wavelength system.
2Reliability
If filter regions are arranged to equalize optical path lengths, then optical signal loss is reduced, but the arrangement becomes more complex
Solution Approach 1:
The patent achieves equalized optical path lengths and improved reliability by inverting the filter region arrangement. The reception filter is configured with regions in reverse order compared to the transmission filter, ensuring that light signals of all wavelengths undergo the same number of bounces (8 bounces) and traverse equal optical path lengths. This systematic inversion approach improves transmission reliability while maintaining a relatively simple implementation strategy.
3Loss of energy
If the number of bounces is reduced for all wavelengths, then optical power loss is minimized, but the optical system design becomes more challenging
Solution Approach 1:
The patent reduces optical power loss by inverting the filter region order, which equalizes the number of bounces to 8 for all wavelengths. While this improves energy efficiency, it does increase design and assembly complexity as the filter regions must be precisely arranged in reverse order. The patent addresses this by providing a systematic method for configuring the inverted filter arrangement.
Solution Approach 2:
The patent changes the arrangement parameter of filter regions from conventional order to inverted order. This parameter change directly reduces the number of bounces from 14 to 8 for the worst-case wavelengths, thereby minimizing optical power loss. The systematic nature of this parameter change provides a clear design guideline for manufacturing and assembly.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces maximum optical power losses by equalizing the number of bounces for each wavelength, from 14 to 8 in a four-wavelength system, thereby minimizing power loss and enhancing the efficiency of CWDM systems.
Implementation Method 1
Each one of the different regions may be associated with a different wavelength and configured to allow light signals of the corresponding wavelength to pass through the filter while reflecting light signals of other wavelengths
Data Source
AI summary
In example implementations, an apparatus is provided. The apparatus includes an optical transmission component and an optical reception component. The optical transmission component includes a plurality of lasers and a transmit filter. The plurality of lasers each emit a different wavelength of light. The transmit filter includes a plurality of different regions that correspond to one of the different wavelengths of light emitted by the plurality of lasers. The optical reception component includes a plurality of photodiodes and a complementary reverse order (CRO) filter. The CRO filter includes a same plurality of different regions as the transmit filter in a reverse order.